The problem associated with cargo losses has been present since the earliest of times. Ever since valuable cargos have been transported over land or sea, and more recently through the air, the temptation has been presented to those who handle such cargos to misappropriate all or a portion of the cargo. Piracy of cargos is also of ancient origin, and continuos today.
Modern cargo security systems for protecting cargo from unauthorized tampering, theft, alteration or deliberate contamination typically employ passive and active safeguards and deterrents, and combinations thereof.
One well known example of a passive safeguard is a looking mechanism by which the cargo is looked inside of a enclosed container. Anyone, whether authorized or unauthorized, who possesses a key or combination may intrude the locked space without detection or recordal of the event. Also, locks may be tampered with, picked and/or physically removed, so that their deterrent effect is recognized to be limited. Seals are also used to deter employees or other insiders from unauthorized access to the cargo within the enclosed container.
One well known example of an active safeguard for stationary premises, such as a cargo warehouse, is an alarm system which senses suspicious events and generates a local alarm or a silent alarm which is sent to a central security agency for further investigation. The alarm system may employ an annuciator such as a horn, light or siren. Such alarm systems are easily disabled, particularly by those who are familar with their structure and function.
Fairly sophisticated security systems for transportation containers for cargo include devices which sense and record mechanically activities and events of the cargo container. For example, U.S. Pat. No. 2,051,986 to H. R. Cool describes a door activities recorder. This device created a record of door activities by recording the opening and closure of the door. A stylus coupled to the door records opening and closure events on a paper record disk which is slowly rotated by a clock motor. The rotations are calibrated, and it is possible later, and with considerable effort, to decipher the recorded markings by time, thereby ascertaining approximately the time and date when the cargo access door was opened and closed.
A later invention by K. A. Cool, described in U.S. Pat. No. 2,616,778, provided a mechanical stylus which punctured the cardboard recording disk, thereby providing a more fixed and permanent record of events, which was less susceptible to alteration or tampering by the driver, etc.
A further variant of the clock recorder is found in U.S. Patent No. 3,720,843, to Smith. The Smith patent discloses a combined vehicle activities and cargo door activities recorder. Therein, a disk chart recorder operated by a clock motor records the status of the vehicle as in motion or at rest, and when the cargo doors are opened and closed; different stylus markings being provided for the opening and closing events.
A drawback of all wind-up clock motors is that they may not keep accurate time. Also, they may stop running, or be stopped or slowed by tampering, and thus yield an inaccurate record of events.
Another drawback of helical records on disks as provided for example by the foregoing systems was the difficulty and considerable time required in decoding and reconstructing events after the fact, should the need arise.
A more sophisticated cargo security device is described in the U.S. Pat. No. 3,792,493 to Hughes. This reference teaches an electronic "black box" device which is installed in a cargo transporting vehicle or container. It contains its own battery power supply which is charged by the vehicle charging system. It includes an electronic clock, cargo door sensor, and a memory element in which the times of door opening/closure events are digitally stored. The memory element operates a visual display and may also drive a chart recorder for providing a hard copy record of door activity. This system simply translated to digital processing the recording and monitoring activities which had previously been carried out with the prior helically graphed records described in the Cool references above.
Recently, vehicle navigation devices have been proposed for simultaneously sensing vehicle direction and speed and for displaying vehicle location in relation to a map display generated electronically. One such system, the ETAK NAVIGATOR manufactured by Etak, Inc., Menlo Park, Calif. employs solid state flux gate sensors to detect the direction in which the vehicle is travelling. This system presents to the driver a road map of the general vicinity which is generated from prestored data. The map is presented on a suitable display. While this system achieves its purpose, it is very complicated and expensive: each unit in the vehicle must contain a wide variety of prestored programs corresponding to road maps of the area of travel. The wider the area, the more extensive the requirement for prestored data in order to render the system operative.
A hitherto unsolved need has arisen for an integrated cargo transportation security system for a fleet of cargo containers, such as truck trailers, which is capable of recording data relating to a cargo transportation event or trip by real time, direction and distance of travel, and by the occurrence of unauthorized events, such as unauthorized opening of a cargo door, and which lends itself to rapid signalling, and decoding and display mapping of the trip course on a roadmap with significant events clearly charted.